Improving Regulation of Enzymatic and Non-Enzymatic Antioxidants and Stress-Related Gene Stimulation in Cucumber mosaic cucumovirus-Infected Cucumber Plants Treated with Glycine Betaine, Chitosan and Combination

Abstract

Cucumber mosaic cucumovirus (CMV) is a deadly plant virus that results in crop-yield losses with serious economic consequences. In recent years, environmentally friendly components have been developed to manage crop diseases as alternatives to chemical pesticides, including the use of natural compounds such as glycine betaine (GB) and chitosan (CHT), either alone or in combination. In the present study, the leaves of the cucumber plants were foliar-sprayed with GB and CHT—either alone or in combination—to evaluate their ability to induce resistance against CMV. The results showed a significant reduction in disease severity and CMV accumulation in plants treated with GB and CHT, either alone or in combination, compared to untreated plants (challenge control). In every treatment, growth indices, leaf chlorophylls content, phytohormones (i.e., indole acetic acid, gibberellic acid, salicylic acid and jasmonic acid), endogenous osmoprotectants (i.e., proline, soluble sugars and glycine betaine), non-enzymatic antioxidants (i.e., ascorbic acid, glutathione and phenols) and enzymatic antioxidants (i.e., superoxide dismutase, peroxidase, polyphenol oxidase, catalase, lipoxygenase, ascorbate peroxidase, glutathione reductase, chitinase and β-1,3 glucanase) of virus-infected plants were significantly increased. On the other hand, malondialdehyde and abscisic acid contents have been significantly reduced. Based on a gene expression study, all treated plants exhibited increased expression levels of some regulatory defense genes such as PR1 and PAL1. In conclusion, the combination of GB and CHT is the most effective treatment in alleviated virus infection. To our knowledge, this is the first report to demonstrate the induction of systemic resistance against CMV by using GB.

Mitigation the adverse effect of salinity stress on the performance of the tomato crop by exogenous application of chitosan

“…In addition, Akladious and Mohamed (2018) who reported that under salt stress, morphological criteria were significantly suppressed in pepper plants. Chitosan concentration positively improved the plant height of tomato, which might be due to the fact that chitosan contains the amino group which enhance the photosynthetic area of the plants which maximize the photosynthesis and finally it increased the plant height (Sofy et al 2020a). The increment in plant growth after treatment with chitosan may be due to its impact on enhancing uptake and transport of minerals such as nitrogen, phosphorus and potassium.…”

“…Chitosan is made from D-glucosamine and N-acetyl-D-glucosamine. It is made when the acetyl group of chitins is replaced with an amino group (Sofy et al 2020a;Sugiyama et al 2001). It is the most commonly available basic biopolymer and has structural similarity with cellulose (de Alvarenga 2011).…”

“…Chitosan is widely used for Post-harvest coating to improve shelf life and also used to improve growth and yield (Haytova 2013). It also improves plant defense mechanism against both biotic and abiotic stress (Sofy et al 2020a). Chitosan enhances both qualitative and quantitative characteristics of crops because it promotes nutrient uptake of the plant (Malerba and Cerana 2016).…”

Zinc and Paclobutrazol Mediated Regulation of Growth, Upregulating Antioxidant Aptitude and Plant Productivity of Pea Plants under Salinity

“…Under stress conditions, the ROS molecules must be detoxified to reduce injury. Proficient devastation of ROS needs the synchronization of numerous antioxidant enzymes [ 5 , 7 , 10 , 11 , 12 ]. The effect of ROS is mitigated by multiple scavenging enzymes, i.e., SOD, CAT, APX, and GR.…”

“…These include exclusion and compartmentation of toxic ions, as well as overproduction of compatible solutes [ 3 , 7 , 9 ]. Together with nonenzymatic antioxidants (phenolic compounds, carotenoids ”CAR”, flavonoids “FLAV”, ascorbic acid “AsA”, and reduced glutathione “GSH”), plants nullify ROS by upregulating antioxidant enzyme activities that quench O 2 − to H 2 O 2 , and finally into the water and molecular oxygen [ 7 , 10 , 11 ]. Moreover, the assimilation of antioxidant compounds work as a noticeable protection feature under the stressful condition that directly interacts with the detoxifying free radicals [ 4 , 12 ].…”